Explosive time delay



June 3, 1969 v. J. MENICHELLI ETAL EXPLOSIVE TIME DELAY Filed Sept. 28, 1967 h HU H H H 2/ INVENTOR s Vincent J. Menichelli Dante Piacesi,

ATT NEY United States Patent Office Int. Cl. F42c 9/02 U.S. Cl. 102-70 3 Claims ABSTRACT OF THE DISCLOSURE An explosive time delay operating in the microsecond range for providing a predetermined time delay for use with missiles, such as projectiles, which will permit the missile to penetrate a target, such as an airplane, before the main explosive charge carried by the missile is detonated. The time delay is housed within the main explosive charge of the warhead and is initiated by a standard fuze. The time delay has a tubular barrel-like housing with an explosive train therein which is made up of a series of secondary high explosive pellets separated by air gaps. On the aft end of each secondary high explosive pellet is a metal disc. Upon initiation of the first explosive pellet, kinetic energy is imparted to the metal disc associated therewith. The metal disc is then accelerated across the air gap and impinges on the explosive pellet of the succeeding stage. Upon impact, the explosive in the second stage is detonated, accelerating the second disc. This process is repeated for as many stages as desired; each stage contributing a delay time. The delay time is obtained because the metal disc velocity is less than the detonation velocity of the secondary explosive.

Background of the invention The invention generally relates to a time delay, and more particularly to an explosive time delay operating in the microsecond range.

Antiaircraft missiles, such as projectiles, will detonate upon impact with the target, such as an airplane, generally causing damage to the external configuration of the aircraft without doing substantial damage to the interior thereof. It has been found desirable to incorporate in antiaircraft projectiles a delay which will permit the missile to penetrate the target before the main explosive charge carried by the missile is detonated thereby to effect maximum damage to the target. The delay time necessary to permit missile penetration is in the microsecond range, and consistently accurate delays in the microsecond range are essentially unknown in the prior art. A burning pyro technic column has been used as a time delay, but burning occurs in the millisecond range and is not Wholly satisfactory for the intended purpose. It is well known in pyrotechnics that burning occurs in the millisecond region whereas detonation occurs in the microsecond region.

Summary of the invention It is accordingly an object of the present invention to provide a time delay within the microsecond range for use with ordnance vehicles, such as projectiles, which will permit the missile to penetrate a target, such as an aircraft, before the main explosive charge carried by the missile is detonated.

Another object is to provide an explosive time delay utilizing a secondary high explosive which may be dis posed within the main explosive charge carried by a missile.

A further object of the present invention is to provide an explosive time delay for use with missiles which will have an accurately predetermined functioning time within the microsecondrange.

as rep- 3,447,464 Patented June 3, 1969 The foregoing and other objects are attained by an explosive time delay utilizing a detonating explosive to propel a small steel disc across an air space to provide delay times in the microsecond range. The delay time is obtained because the metal disc velocity is less than the detonation velocity of the secondary explosive used. A more complete appreciation of the invention and many of the attendant advantages thereof will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing.

Brief description of the drawing The solitary figure of the drawing is a longitudinal central sectional view through a missile nose portion, such as a projectile, showing the explosive time delay with in the main explosive charge of the missile.

Description of the preferred embodiment Referring in detail to the drawing, the explosive time delay 1 is shown as housed within the main explosive charge 2 of a projectile 3 having a safing and arming fuze 4 attached to the forward end thereof. The explosive time delay 1 is initiated upon impact of the safing and arming fuze 4 with a target.

The safing and arming fuze 4 has an explosive charge 5 disposed within a rotor 6 which upon rotation into the armed position, as shown, is adapted to move into alignment with a hammer 7 and a firing pin 8 for initiation of the explosive charge 5 upon impact. Upon detonation of the explosive charge 5 a lead-in 10 in alignment therewith will detonate a booster charge 11 for initiation of the explosive time delay 1. The details of the rotor and mechanism for moving it to armed position form no part of this invention, these details being the invention of Winfred F. Sapp, disclosed in U.S. patent application Ser. No. 342,039, filed Mar. 12, 1953, and now Patent No. 2,948,219.

The explosive time delay train 1 is contained within a cylindrical housing 12, and is made up of a predetermined number of charges of explosive composition such as pellets 13 separated from each other by air gaps 14. The pellets 13 are preferably made of a secondary explosive material such as tetryl or TNT. Since secondary explosives are substantially safer than the primary high explosives normally used in time delays, the delay mechanism can be housed within the high explosive charge of the projectile and need not be incorporated within the arming mechanism in the projectile. Since there is generally a great deal of space within the high explosive charge of the rocket, there is a distinct advantage in being able to mount the delay mechanism within the explosive itself.

Adjacent the aft end of each pellet 13 is a member composed of non-exposive material illustrated as steel discs 15, having a diameter substantially the same as the internal diameter of housing 12. Upon initiation of the first explosive pellet 13, kinetic energy is imparted to the metal disc 15 adjacent thereto. The metal disc 15 is then accelerated across the air gap 14, and impinges on the ex plosive pellet 13 of the succeeding stage. Upon impact, the explosive in the second stage is detonated accelerating the second disc. This process is repeated for as many stages as desired, each stage contributing a delay time. Since detonation occurs essentially instantaneously, the delay time desired is obtained because the metal disc velocity is less than the detonation velocity of the secondary explosive pellets. The last pellet of explosive material in the delay train does not have a steel disc 15 associated therewith, and detonation of the last explosive pellet 13 causes detonation of the main explosive charge 2.

detonable composition within said normally abutting said first charge in the space between said first and second charges and spaced from said second charge capable of being propelled across said spacing between said charges upon detonation of said first charge for detonating said second charge a predetermined time delay in the microsecond range after the detonation of said first charge.

2. The explosive time delay of claim 1 further comprising a predetermined number of spaced charges of detonable composition longitudinally aligned with and spaced from said first and second charges, and

a disc of non-explosive material for each of said predetermined number of spaced charges, each having one side thereof normally abutting its respective charge and spaced from the next succeeding charge and capable of being propelled upon detonation of said respective charge for successively detonating said charges in response to detonation of said first charge with a predetermined time delay in the microsecond range between successive detonations.

3. The explosive time delay of claim 1 wherein said charges are in the form of secondary high explosive pellets, and

said disc is constructed of metal.

References Cited UNITED STATES PATENTS 2,823,609 2/1958 Johnson et a1 10227 3,045,524 7/1962 Stresau et a1. 3,154,013 10/1964 Miller 102-1 3,162,127 12/1964 Breslow et al. 10285 3,169,480 2/1965 Seavey 10227 2,883,931 4/1959 Houck et al 10227 X BENJAMIN A. BORCHELT, Primary Examiner.

G. H. GLANZMAN, Assistant Examiner.

US. Cl. X.R. 

